The number
Aim for 1.2 to 1.6 grams of protein per kilogram of body weight, every day, the whole time you’re on semaglutide or tirzepatide. At 200 lbs, that’s roughly 110–145 grams a day, including the days you have no appetite.
For calibration: the RDA is 0.8 g/kg. That’s a floor for weight-stable adults, and on a GLP-1 you are not weight-stable. The 1.2–1.6 band is the standard countermeasure against muscle loss during rapid weight loss. It is an extrapolation: no one has run a large trial randomizing protein targets in GLP-1 users specifically, so the band comes from the broader weight-loss literature. We use it because the logic is strong and the cost of following it is close to zero.
Your weight, in grams
- 160 lb (73 kg): 90–115 g/day
- 180 lb (82 kg): 100–130 g/day
- 200 lb (91 kg): 110–145 g/day
- 220 lb (100 kg): 120–160 g/day
- 250 lb (113 kg): 135–180 g/day
In meal terms: three meals built around 30–40 g each, plus one 20–25 g snack. That lands in the band at most weights. Above 220 lbs, the top of the range takes a second shake.
At higher body weights the per-kilogram math climbs fast, and many clinicians anchor the target to goal weight rather than current weight. That anchor is a decision to make with your clinician; the band itself doesn’t change.
Why the number is high
Semaglutide and tirzepatide cause weight loss one way: you eat less. They slow gastric emptying and act on the hypothalamic and hindbrain circuits that generate appetite, so intake falls steeply and stays down. The losses are large — 14.9% of body weight at 68 weeks in STEP 1 (semaglutide, n=1,961), up to 20.9% at 72 weeks in SURMOUNT-1 (tirzepatide, n=2,539). Weight loss that fast always includes lean tissue, not just fat; in DXA substudies, a meaningful share of what’s lost is lean mass.
Protein is the half of the countermeasure you can eat. Muscle in a deficit is continuously broken down and rebuilt, and amino acid supply decides whether the rebuilding keeps pace. The other half is giving muscle a reason to stay: resistance training about twice a week, covered in strength and recovery.
What we don’t know: whether the lean mass lost on these drugs shows up as weakness or lost function five or ten years from now. That data doesn’t exist yet. Our position is to protect the muscle anyway. If long-term follow-up shows strength holds without the extra protein, this advice can relax; until then, the insurance is cheap.
Eating it when you’re not hungry
Knowing the number is easy. Eating 130 g on a stomach that fills fast and empties slowly is the real problem. Three rules do most of the work:
- Protein first, everything else second. Fullness arrives early and ends the meal. If the chicken comes after the rice, the chicken doesn’t get eaten.
- Don’t save protein for dinner. If you’re 80 g behind at 6 p.m., you won’t catch up. Get 30 g in before noon.
- Let liquids carry the bad days. A 30 g shake, Greek yogurt, cottage cheese: they go down when nothing else will, and they count exactly as much as chicken does.
For the meals themselves, see twelve meals that clear 30 g in under 10 minutes. The GLP-1 food guide covers how protein fits alongside fiber, fluids, and dose-day eating.
Count for three days
Find your line in the list above. Log everything with protein in it for three days — an app or a notes file, either works — and measure the gap. Then close it one meal at a time, starting with breakfast; a shake and one rebuilt morning meal go further than any dinner overhaul. And if you’re not on a GLP-1 yet and want to know whether you’d qualify, take the quiz.
